Most investors set up a portfolio. Then they forget about it. Months later, they check in and find out their "balanced" portfolio is no longer balanced.
Stocks took off. Bonds barely moved. Now they are running a much riskier portfolio than they signed up for. That is the moment rebalancing matters. Here is how to do it.
What It Means To Rebalance A Portfolio
Rebalancing is the process of adjusting your portfolio back to your target allocation when it drifts. Here is the scenario. You start the year with a portfolio that is 70% stocks and 30% bonds.
(For a refresher on the difference between stocks and bonds, that piece covers the basics.) That is your target based on your risk tolerance and time horizon. Fast forward nine months.
The stock market has had a great run and is up 20%. Your bonds are up 3%. Your portfolio is no longer 70/30. It is now closer to 75/25.
You have unintentionally become more aggressive than you planned. Rebalancing is selling some of your winners and buying more of your underperformers to get back to where you started. You are probably already thinking, "Why would I sell my winners?" Here is why.
Why You Should Rebalance Your Portfolio: Buy Low, Sell High On Autopilot
Rebalancing forces you to do the most important thing in investing - buy low and sell high. When you rebalance, you sell assets that have gone up in price. That is selling high.
Then you buy assets that have lagged. That is buying low. You are taking profits from your winners and rotating into assets that are now relatively cheaper. That is the exact opposite of what most investors do on emotion alone. Most people chase what is hot.
Rebalancing makes you do the opposite, automatically. (It is the kind of discipline that defines a real investing mindset - thinking long-term and overriding emotion.)
It is also a risk management strategy. If you never rebalance, your portfolio can become dangerously concentrated in whatever has been performing best. In the late 1990s, investors who did not rebalance ended up with 80% to 90% of their portfolio in tech stocks.
When the dot-com bubble burst, they lost everything. Rebalancing prevents that. It keeps your risk level steady. (For more on why even smart investors panic when concentrated positions blow up, see our piece on the psychology of market crashes.)
How To Rebalance Portfolio Step 1: Set Your Target Allocation
You cannot rebalance without a target. Your target allocation depends on your risk tolerance and time horizon.
You can also break stocks down further into U.S. stocks, international stocks, and small caps. Same with bonds. The more granular your targets, the more often you will need to rebalance.
One popular structure is the core-satellite portfolio, which keeps a stable core of index funds with smaller satellite picks around it.
It is a clean way to set up a portfolio that is easy to rebalance. Within your stock allocation, your "core" might be a low-cost index fund tracking a major benchmark - many investors anchor their portfolio with an S&P 500 index fund and add satellites from there.
Choosing between ETFs, mutual funds, and index funds depends on the kind of accounts you have and how often you trade. Pick a setup that fits you. Write it down. That is the plan you will rebalance back to.
How To Rebalance Portfolio Step 2: Pick Your Rebalancing Trigger
There are two ways to decide when to rebalance.
Time-based rebalancing. You rebalance on a schedule. Once a year, twice a year, or once a quarter. Many investors rebalance every January 1st. It is simple, automatic, and you do not have to think about it.
Threshold-based rebalancing. You rebalance when your allocation drifts more than a set amount from your target. For example, if your target is 70% stocks but it drifts to 75%, you rebalance. Same thing if bonds drift from 30% to 25%. Both work.
Time-based is simpler and does not require constant monitoring. Threshold-based responds faster to market moves but means more checking in. For most investors, once a year is enough. Your rebalancing approach should also match your overall investing style.
If you are mostly a passive investor, time-based rebalancing fits. If you are more active, you may want to track drift more closely.
Our piece on active investing vs passive investing breaks down the difference. The same goes for the kinds of stocks you hold - someone who runs a value investing portfolio rebalances differently than someone leaning into growth stock investing.
How To Rebalance Portfolio Step 3: Execute The Trades
Once you decide your portfolio has drifted, you actually have to make the moves. Inside your brokerage account, this looks like:
- Calculate your current allocation. Add up the dollar value in each asset class.
- Compare to your target. Find what is over and what is under.
- Sell the overweight positions. Use that money to buy the underweight ones.
Many brokerages have built-in tools that do this calculation for you. Some target-date funds rebalance automatically. There is also a smarter approach for investors still adding money to their portfolio.
How To Rebalance A Portfolio With New Contributions (No Selling Needed)
If you are still in the accumulation phase - meaning you are adding money regularly - you can rebalance without selling anything. Here is how. Instead of selling your winners, just direct new contributions to whatever asset class is underweight.
Over time, the new money tilts the balance back toward your target. This works especially well if you are dollar cost averaging. You are already adding money on a schedule. All you do is pick where each new contribution goes.
The big advantage is taxes. When you sell a winning position in a regular taxable account, you owe capital gains tax. When you simply direct new money to an underweight asset, you do not trigger any tax. You just keep buying.
For investors with mostly retirement accounts, taxes are not an issue inside the account. But for taxable accounts, this is a much smarter way to rebalance.
How To Rebalance Portfolio: A Real Example
Let's run through a quick example. Sarah has $100,000. Her target is 70% stocks, 30% bonds. So she has:
- $70,000 in stocks
- $30,000 in bonds
After a year, the stock market is up 25% and her bonds are up 4%. Now she has:
- $87,500 in stocks
- $31,200 in bonds
- Total: $118,700
Her actual allocation is now about 74% stocks and 26% bonds. She has drifted past 5%. To rebalance, she sells $4,400 of stock and buys $4,400 of bonds. Now she has:
- $83,100 in stocks (70%)
- $35,600 in bonds (30%)
She locked in some stock gains and added to bonds while bonds were lagging. That is buy low, sell high. If Sarah is also adding $1,000 a month to her portfolio, she could just direct her next several months of contributions to bonds instead. No selling needed.
When To Rebalance Your Portfolio Extra Carefully
A few special cases. Big market drops. If the market drops 20%, your stock allocation will fall. That actually means you need to buy more stocks to rebalance.
This is hard emotionally - everyone else is panicking. But it is exactly when rebalancing pays off. (Related read: our guide on how to invest during a recession - savvy investors treat downturns as sales.) Big market run-ups. If the market is up huge, your stocks will be overweight.
Selling some feels wrong because everything looks great. That feeling is exactly why rebalancing is valuable. The same logic applies between bull markets and bear markets - rebalancing keeps your risk level steady through both. Approaching retirement. Within 5 to 10 years of retirement, most people shift to a more conservative allocation.
That is itself a kind of rebalancing - just a one-time change in the target. This is also when wealth planning starts to matter more, since the goal shifts from growing wealth to protecting it.
Common Portfolio Rebalancing Mistakes To Avoid
A few things to watch out for.
- Rebalancing too often. Once a year is fine for most investors. Doing it monthly or quarterly creates more taxable events and trading costs without much extra benefit.
- Forgetting taxes. In taxable accounts, every sale can trigger capital gains tax. Use new contributions when you can.
- Ignoring drift. The opposite mistake. Some investors set a portfolio and never check on it. Five years later, they are running a totally different allocation than they planned.
- Chasing the hot pick. Rebalancing is the opposite of chasing. If you are trying to figure out the best stocks to buy now, do that within your target allocation - not as a reason to abandon it.
- Forgetting income. Rebalancing also affects your income side. If part of your strategy is dividend investing, make sure rebalancing does not accidentally crush your dividend stream.
How To Rebalance Portfolio: The Bottom Line
How to rebalance portfolio is one of the most underrated skills in investing.
It forces discipline. It keeps your risk steady. And it builds in a buy low, sell high mechanism without you having to time anything. Pick your target. Pick your trigger.
Do it once a year, or whenever drift hits 5%. If you are still adding money, use new contributions to do the work for you. Boring? Yes. Effective? Absolutely.
